This invention relates generally to a tamper resistant bait station for holding a supply of toxic pest bait, such as a rodenticide pellet or powder (or other poisonous substance), to be ingested or externally contacted by undesired pests (e.g., mice, rats, snails, or slugs).
For a number of years, it has been conventional, particularly in large commercial buildings, food warehouses, restaurants, farm buildings, schools, and even in human residences, to use a poisonous bait or poisonous tracking powder to poison undesired pests. Even more particularly, in the control of mice and rats, zinc phosphide, and anti-coagulant rodenticides have been widely used. Generally, all such rodenticide baits and bait concentrates approved for use by the United States Environmental Protection Agency require labeling to the effect that baits must be placed in tamper proof bait boxes or in locations not accessible to children, pets, domestic animals, or protected wildlife. Further, warnings are given not to place the bait in areas where there is a possibility of contaminating food for human consumption or of contaminating surfaces that come in contact with food. Also, it is highly desirable that powdered baits not be positioned so that it may be disturbed by air currents and thus drawn into ventilation ducts or blown onto food or food contact surfaces.
Prior to and during World War II in England, considerable research was done in regard to bait containers for field use. In 1954, a publication entitled Control of Rats and Mice, pp. 147-159, published by Oxford University Press, London, described two types of bait containers, the first being a specially shaped box in which the bait is inaccessible to animals other than rodents and the other being a blocked drain pipe. The bait box described in the above-identified publication was also disclosed in British Pat. No. 541,844. Generally, this bait box had an enclosed chamber in which the bait was placed with an access opening being provided in the bottom floor defining the chamber so that the rodents may enter the bait box from below. However, it had been noted by the inventors of the above-identified British patent specification that wildlife, such as field sparrows, could enter this prior bait box and gain access to the poisoned bait. Also, because of the design of this prior bait box, it would be possible for a child to reach his hand into the access opening of the bait box and also have direct access to the bait.
Reference may also be made to such U.S. Pat. Nos. 794,323, 1,086,610, 1,309,606, 2,299,723, 3,045,387, 3,965,609, 4,208,829, 4,228,613, 4,251,946, which disclose various permanent bait stations for holding a supply of toxic rodent bait or the like. Generally speaking, these prior bait stations have tamper proof access openings or closures, but each of these prior bait stations has certain drawbacks, particularly when considered in light of the more recent United States Government Environmental Protection Agency regulations dealing with rodenticide baits.
Still further, such U.S. Pat. Nos. 3,298,128, and 4,031,653 disclose various foldable bait stations of fibreboard material, plastic or the like. However, as is intended for these fibreboard bait stations, they do not offer the security required for a permanent bait station and these fiberboard bait stations are intended to be disposed of regularly.
U.S. Pat. No. 4,062,142 discloses a trapping and killing apparatus for mice which traps a live mouse therewithin and which automatically dispenses a quantity of poisonous gas so as to kill any mouse trapped therein.
U.S. Pat. No. 4,251,946 discloses a snail and slug trap wherein the bait is a pesticide which is activated by water contained within a water reservoir.
Lastly, U.S. Pat. No. 4,281,471 discloses a rodent tunnel in the form of an elongate tube so that mice will run through the tube. Cartridges of a suitable contact rodenticide are placed at intervals along the tube such that the mice come into contact with the rodenticide as they travel through the tube and become fatally affected by it.